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Title: Using Mixed Salt Electrolytes to Stabilize Silicon Anodes for Lithium-Ion Batteries via in Situ Formation of Li–M–Si Ternaries (M = Mg, Zn, Al, Ca)

Abstract

Replacing traditional graphite anode by Si anode can significantly improve the energy density of lithium-ion batteries. Yet, the large volume expansion and the formation of highly reactive lithium silicides during charging cause the continuous lithium and electrolyte consumption as well as the fast decay of Si anodes. In this work, by adding 0.1 M M(TFSI) x (M = Mg, Zn, Al and Ca) as a second salt into the electrolyte, we stabilize the anode chemistry through the in situ formation of Li–M–Si ternary phases during the charging process. First, lithium silicides and magnesium lithium silicides were synthesized as model compounds to investigate the influence of metal doping on the reactivity of lithiated Si. Using solid-state nuclear magnetic resonance spectroscopy, we show that Mg doping can dramatically suppress the chemical reactions between the lithium silicide compounds and common electrolyte solvents. New mixed salt electrolytes were prepared containing M(TFSI)x as a second salt to LiPF6 and tested in commercially relevant electrodes, which show higher capacity, superior cyclability, and higher Coulombic efficiencies in both half-cell and full-cell configurations (except for Zn) when compared with standard electrolytes. Post-electrochemistry characterizations demonstrate that adding M salts leads to the co-insertion of M cations along with Limore » into Si during the lithiation process, stabilizing silicon anions by forming more stable Li–M–Si ternaries, which fundamentally changes the traditional Li–Si binary chemistry while minimally affecting silicon electrochemical profiles and theoretical capacities. This report opens a new and simple way to stabilize silicon anodes to enable widespread application of Si anodes for lithium-ion batteries.« less

Authors:
 [1];  [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1558122
Alternate Identifier(s):
OSTI ID: 1558232
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Published Article
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 11; Journal Issue: 33; Journal ID: ISSN 1944-8244
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Si anodes; stability; lithium-ion battery; electrolyte additive; mixed salt electrolyte; prelithiation

Citation Formats

Han, Binghong, Liao, Chen, Dogan, Fulya, Trask, Stephen E., Lapidus, Saul H., Vaughey, John T., and Key, Baris. Using Mixed Salt Electrolytes to Stabilize Silicon Anodes for Lithium-Ion Batteries via in Situ Formation of Li–M–Si Ternaries (M = Mg, Zn, Al, Ca). United States: N. p., 2019. Web. doi:10.1021/acsami.9b07270.
Han, Binghong, Liao, Chen, Dogan, Fulya, Trask, Stephen E., Lapidus, Saul H., Vaughey, John T., & Key, Baris. Using Mixed Salt Electrolytes to Stabilize Silicon Anodes for Lithium-Ion Batteries via in Situ Formation of Li–M–Si Ternaries (M = Mg, Zn, Al, Ca). United States. doi:10.1021/acsami.9b07270.
Han, Binghong, Liao, Chen, Dogan, Fulya, Trask, Stephen E., Lapidus, Saul H., Vaughey, John T., and Key, Baris. Thu . "Using Mixed Salt Electrolytes to Stabilize Silicon Anodes for Lithium-Ion Batteries via in Situ Formation of Li–M–Si Ternaries (M = Mg, Zn, Al, Ca)". United States. doi:10.1021/acsami.9b07270.
@article{osti_1558122,
title = {Using Mixed Salt Electrolytes to Stabilize Silicon Anodes for Lithium-Ion Batteries via in Situ Formation of Li–M–Si Ternaries (M = Mg, Zn, Al, Ca)},
author = {Han, Binghong and Liao, Chen and Dogan, Fulya and Trask, Stephen E. and Lapidus, Saul H. and Vaughey, John T. and Key, Baris},
abstractNote = {Replacing traditional graphite anode by Si anode can significantly improve the energy density of lithium-ion batteries. Yet, the large volume expansion and the formation of highly reactive lithium silicides during charging cause the continuous lithium and electrolyte consumption as well as the fast decay of Si anodes. In this work, by adding 0.1 M M(TFSI)x (M = Mg, Zn, Al and Ca) as a second salt into the electrolyte, we stabilize the anode chemistry through the in situ formation of Li–M–Si ternary phases during the charging process. First, lithium silicides and magnesium lithium silicides were synthesized as model compounds to investigate the influence of metal doping on the reactivity of lithiated Si. Using solid-state nuclear magnetic resonance spectroscopy, we show that Mg doping can dramatically suppress the chemical reactions between the lithium silicide compounds and common electrolyte solvents. New mixed salt electrolytes were prepared containing M(TFSI)x as a second salt to LiPF6 and tested in commercially relevant electrodes, which show higher capacity, superior cyclability, and higher Coulombic efficiencies in both half-cell and full-cell configurations (except for Zn) when compared with standard electrolytes. Post-electrochemistry characterizations demonstrate that adding M salts leads to the co-insertion of M cations along with Li into Si during the lithiation process, stabilizing silicon anions by forming more stable Li–M–Si ternaries, which fundamentally changes the traditional Li–Si binary chemistry while minimally affecting silicon electrochemical profiles and theoretical capacities. This report opens a new and simple way to stabilize silicon anodes to enable widespread application of Si anodes for lithium-ion batteries.},
doi = {10.1021/acsami.9b07270},
journal = {ACS Applied Materials and Interfaces},
number = 33,
volume = 11,
place = {United States},
year = {2019},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1021/acsami.9b07270

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